This invention relates generally to fences. More specifically, it provides fences--as of the garden border and like type--formed of a rigid plastic material and which are laterally flexible to follow a contour but yet are self-supporting and formed in indefinite lengths.
Fences are widely used in landscaping and gardening to protect and decorate shrubs, gardens, flower beds, trees and the like. Such a fence must be strong enough to withstand the mechanical stresses of handling, installation and relocation, particularly where it is supported by thrusting a projecting stake portion into the ground. The fence should also be laterally flexible to curve around trees and corners, or decorative contours of gardens and flower beds. It is also important for the fence to have an aesthetically pleasing appearance and to resist deterioration under adverse weather conditions.
Wooden picket fences that have a relatively short vertical height are a traditional form of shrub fence. The pickets are joined together either by wire strands or by wooden rails, typically in three foot lengths. Both forms of these wooden fences are relatively heavy and cumbersome, and require periodic maintenance. In addition, the wire links tend to rust and they fatigue after repeated flexing. The wooden rail sections, on the other hand, are inflexible and generally are available only in such short lengths.
U.S. Pat. Nos. 2,685,432; 2,696,974 and 2,962,263 describe metallic fences where flexibility is provided by a metal band that connects the vertical slats. While metallic fences have certain strength advantages as compared to wood fences, and can simulate the appearance of wood fences, they generally suffer from a higher cost of manufacture, they are generally heavier, and they require anti-corrosion protection and maintenance. Further, because these fences typically are formed of sheet metal to control cost and weight, they usually cannot be driven directly into the ground, but instead require auxiliary support stakes or posts.
Other metallic fences, which avoid these cost and weight problems, are formed of wire bent into segments, often in the general shape of inverted U's, that are hinged together. The lower ends of each section are pushed into the ground to support the fence. While these and other wire fences are fairly flexible and self-supporting, they are comparatively weak and have only a minimal visual impact. In particular, they do not offer the aesthetic and decorative advantages of traditional picket, scroll and other fence structures.
In recent years, plastic materials have been used for fences. U.S. Pat. No. 3,877,140, for example, describes a wire-connected snow fence having vertical slats of plastic sheet. The slats are interconnected by strands of wire that run horizontally through each slat, or by webs of the plastic sheet which forms the slats. One disadvantage of this fence is that the sheet material is so weak that each slat must be creased vertically to stiffen it, and the fence as a whole must be supported by other structure. Other disadvantages are that the wire is prone to rust and metal fatigue, and is likely to separate from the thin plastic.
Plastic shrub fences presently on the market generally fall into two categories, flexible fences of polyethylene and rigid fence sections of polystyrene. The polyethylene fences sacrifice strength for flexibility and therefore, under normal conditions, require auxiliary supports. Also the polyethylene material frequently softens and the colors fade when exposed to sunlight. The polystyrene fence sections, typically sold in three-foot lengths and designed to simulate wrought iron, are sufficiently rigid to be driven directly into the ground for support. But like the wooden sectional fences, they are inflexible and therefore ill-suited to many landscaping situations.
It is therefore a principal object of this invention to provide a plastic fence that is rigid, strong and self-supporting while at the same time is highly laterally flexible and capable of being formed in indefinite lengths.
Another object of this invention is to provide a structure for a plastic fence having the foregoing advantages and suited for attractively simulating different traditional fence designs.
Yet another object of the invention is to provide a fence of the above character and which does not deterioriate due to exposure to weather and requires minimal maintenance.
A further object of this invention is to provide such a fence that is lightweight and convenient to ship, store and install.
Still another object is to provide a fence with the foregoing advantages that is adapted to high volume, low-cost production techniques. A corollary object is to provide such a production method for a fence of the foregoing character.